[Urgent] Being a secondary school teacher

I am leaving my town to take over a new task as a secondary school teacher in a town nearby. I will teach them *simple* programming courses with Java language (I guess the principal wanted them to learn java networking basics and introductory lessons in jsp technology). I am both excited and worried as this is my first pay of being a real teacher. Do you have any advice and hints to *foresee* what might be the possible outcomes as well as confronts I will have to deal with ? Thank you a lot.